The present invention relates to intermediate filament or yarn storage and feeding devices used in association with textile producing apparatus, particularly knitting machines, but relating as well to weaving and spooling apparatus.
Storage feeding devices are well known in the prior art and comprise usually a storage element such as a drum, about which yarn is wound tangentially to form a supply of yarn or store thereon which is then removed axially in response to the demand of the textile producing apparatus. Such storage devices are also known as demand feeders since they make available to the textile producing apparatus the amount of yarn demanded thereby. Examples of such storage or demand feeders are shown in U.S. Pat. Nos. 3,225,446, 3,419,225, 3,648,939 and 3,780,958. During the axial withdrawal of the yarn from the storage member, it is desirable to retard the yarn by means of a retarding device so that the yarn being withdrawn has imparted thereto a constant uniform tension which is generally very low. Such retarding devices have assumed various forms in the prior art as for example a resilient ring such as shown in U.S. Pat. No. 3,225,446 or a base ring surrounding the storage drum and having flexible elements such as resilient fingers extending inwardly from the ring for engagement with the drum such as shown in U.S. Pat. Nos. 3,648,939 and 3,702,176.
As the yarn is axially removed from the storage member, it passes between the drum and the retarding device with the latter imparting to the yarn a retarding force and thus a predetermined tension intended to be uniform.
In accordance with the present invention, there is provided a retarding device which is of substantially improved construction and which is particularly well adapted for use in connection with a storage feeding device wherein the yarn which is axially withdrawn from the drum reverses direction and passes through a passageway within the storage drum on its way to the textile producing apparatus, such as shown in U.S. Pat. No. 3,780,958.
It is also known in the prior art to provide storage feeding devices which can be converted into positive feeding devices wherein the yarn, instead of being withdrawn axially, is withdrawn tangentially at a predetermined rate directly related to the rotational rate of the knitting machine. Examples of yarn feeding devices which can be selectively operated as storage feeding devices or positive feeding devices are shown in U.S. Pat. Nos. 3,782,661 and 3,796,384. It is another object of the present invention to provide greatly simplified means for enabling an intermediate yarn feeding device to be selectively operable either as a demand feeder wherein the yarn is axially withdrawn in response to the demand of the textile feeding apparatus, or as a positive feeder wherein the textile producing apparatus is positively fed a predetermined amount of yarn per unit of time, as determined by the rotational speed of the apparatus.